Insecticide-containing netlike fabric

ABSTRACT

The present invention relates to an insecticide-containing fabric containing at least one embedded insecticidally active ingredient in the polymeric matrix and having excellent wash resistance, and also to the products produced from this fabric and to their use for protecting humans, animals and plants against arthropods, particularly for controlling insects.

The present invention relates to an insecticide-containing netlikefabric containing at least one embedded insecticidally active ingredientin the polymeric matrix and having excellent wash resistance, and alsoto the products produced from this netlike fabric and to their use forprotecting humans, animals and plants against arthropods, particularlyfor controlling insects.

It is well known that humans can be protected in their sleep fromarthropod stings by insecticide-coated sleeping nets. This isparticularly important in countries in which arthropods transmitdiseases (malaria for example). Coated fabrics can also be used asdrapes in front of windows or doors in order to control arthropodsentering dwellings. Similarly, using coated fabrics to cover vegetablesor fruits is known as a way of protecting against arthropods. This makesit possible to minimize the contamination with insecticides of the plantparts which are eaten later.

The known materials for nets are essentially polyesters andpolyethylene, which, however, only have limited durability (polyester inparticular) and partly have surfaces sensed to be unpleasantly brittleto the touch (polyethylene in particular). Therefore, it would bedesirable to develop materials based on other, more durable andmechanically more robust polymers.

WO-A2 2008/004711 discloses for example netlike insecticide-containingmaterials based on polyolefins such as polyethylene and/orpolypropylene. Pyrethroids are mentioned as suitable insecticidallyactive ingredients. The insecticidal material is produced bymelt-compounding the thermoplastic polymer with the insecticide and thenextruding the material.

WO-A 2008/032844 likewise describes an insect-repelling materialobtained by melt-spinning a mixture of insecticide and polyethylene.Pyrethroids are mentioned as possible insecticides.

The use of polypropylene is also known from insecticidal evaporatorplatelets (for example WO 97/29634, WO 99/01030, WO 05/044001). Ininsecticidal evaporator platelets, an insecticidally active ingredientis embedded into a polypropylene matrix and quickly released by heatingto above 100° C. in order to treat a room for example. Aroom-temperature use or the use in long-acting materials is notdescribed there, nor a combination with additives.

The use of nets of polyethylene terephthalate (PET) which are coatedwith active component is known for example from the products Permanet®(Vestergaard Frandsen SA, Switzerland) or Dawa® Plus (Tana Netting Co.Ltd., Bangkok, Thailand).

However, the materials known from the prior art have the disadvantage ofsatisfying the criteria of the WHOPES directive (see “Guidelines forlaboratory and field testing of long-lasting insecticidal mosquitonets”, 2005, http://www.who.int/whopes/guidelines/en/) forinsecticide-containing long-lasting mosquito nets up to 20 washes only,which means that such materials tend to lose active ingredient at such ahigh rate that they will have lost their biological activity after just20 wash cycles or so.

The loss of active ingredient from a textile fabric treated with activeingredient, for example from a net treated with insecticide, can bedescribed in terms of a retention index (see: “Report of the EleventhWHOPES Working Group Meeting”, WHO, HQ, Geneva, 10-13 Dec. 2007, Annex1). To determine its retention index, the polymeric material isrepeatedly subjected to a treatment defined in the WHOPES directive.

According to the WHOPES Phase I directive, the tested textiles shallstill have a certain biological activity after they have been subjectedto 20 washes. Either knock-down at 60 minutes post-exposure has to bebetween 95% and 100%, or the mortality at 24 hours post-exposure has tobe between 80% and 100%. Knock-down after exposure of mosquitoes toinsecticides is considered to be the first visible evidence of theefficacy of an insecticide: the mosquitoes are no longer capable ofcoordinated movement, flight or walking, and usually fall on their backswithout, however, being already dead.

Prior to the treatment and following the treatment, theactive-ingredient content of the textile fabric provided with activeingredient is determined. The retention index after n treatments iscalculated from the n-th root of active-ingredient content after ntreatments divided by active-ingredient content prior to treatment.

Netlike textile fabrics used for vector control desirably have aretention index above 95% in order that there may be sufficientbiological activity even after 35 wash cycles. The polymericinsecticide-containing materials known from the prior art haveinsufficient retention indices (between 50 and 90% after 5 washes) whichonly ensure efficacy of the material for a comparatively small number ofwashes and hence for a shorter use life.

Efficacy directly after a wash is of great importance for textilefabrics used for vector control. Fabrics composed of polyethylene forexample, as known from WO-A 2008/032844, experience a post wash cycleloss of their efficacy for some days (the so-called regeneration time),and have to additionally dwell for a certain time at elevatedtemperature to be restored to efficacy. This procedure is inconvenientfor the user and always harbours a risk that this step is not carriedout and that the textile fabric therefore suffers a decrease inprotective performance. A regeneration time of less than two hours isdesirable.

It is an object of the present invention to provide aninsecticide-containing netlike polymeric fabric which reliably meets therequirements of the abovementioned WHOPES directive. The regenerationtime should be less than two hours. In addition, the amount ofactive-ingredient component to be used should be kept as low as possiblewithout compromising the insecticidal effect. Further desiderata are afast-acting insecticidal effect, a uniform release, of active ingredientand also a very simple and inexpensive process of production.

We have found that this object is achieved by the insecticide-containingnetlike polymeric fabric of the present invention.

The present invention accordingly provides a netlike fabric based on aninsecticide-containing polymeric material which has in accordance withWHOPES directive (Phase I) a knock-down after 60 minutes of between 95%and 100% or a mortality after 24 hours of between 80% and 100% after atleast 25, preferably at least 30 and even more preferably at least 35washes.

According to the present invention, the “WHOPES directive” is to beunderstood as meaning the directive “Guidelines for laboratory and fieldtesting of long-lasting insecticidal mosquito nets”, 2005). Thisdirective is retrievable at the following internet address:http://www.who.int/whopes/guidelines/en/.

According to the WHOPES directive, a “washing” is defined as follows: anetlike fabric (25 cm×25 cm) is introduced into a 1 liter beakercontaining 0.5 liters of deionized water and 2 g/l of “Savon deMarseille” soap (pH 10-11) added just before the netlike fabric andfully dissolved in the deionized water. After addition of the netlikefabric, the beaker is immediately introduced into a warm water bath at30° C. and shaken for 10 minutes at 155 movements per minute. Thenetlike fabrics are then removed from the beaker and rinsed twice for 10minutes at a time with clean, deionized water in the same shakingconditions as mentioned above. Thereafter, the netlike fabrics are driedat room temperature and stored at 30° C. in the dark between thewashings.

According to the present invention, the term “knock-down” describes thestate of an animal on its back or side, which is still capable ofuncoordinated movement including short periods of flying.

According to the present invention, the term “mortality” describes animmobile state of animal on its back or side.

Preferably, the netlike fabric of the present invention after at least 5washes in accordance with WHOPES directive has a retention index r ofthe formula (I)r=n√{square root over ((t _(n) /t ₀))}  (I)wheret_(n)=total active ingredient content after n washes (g/kg),t₀=total active ingredient content after 0 washes (g/kg) andn=number of washes,of at least 95%.

The netlike fabric of the present invention based on aninsecticide-containing polymeric material preferably has a regenerationtime of less than 24, preferably of less than 8 and more preferably ofless than 2 hours (tested in accordance with WHOPES directive (phaseI)).

According to the present invention, the term “regeneration time” refersto the time which elapses until the original efficacy is achieved again.

Polymeric materials to be used according to the present invention arepolypropylene and also polypropylene copolymers. Preference is given tousing polypropylene. A multiplicity of polypropylenes are known from theprior art. Polypropylenes can in principle be distinguished according totheir manner of synthesis. The main proportion of polypropylenes isproduced in the presence of Ziegler-Natta catalysts in the suspensionprocess or more particularly in the so-called gas phase process (cf.Kaiser “Kunststoffchemie für Ingenieure”, pages 246 to 254). The gasphase process can also utilize specific catalysts such as metallocenes.The polymers produced using metallocene catalysts are particularlyuseful as polymeric matrix for the insecticide-containing polymericmaterial to be used according to the present invention. The meltingpoints of polypropylenes produced using metallocene catalysts areusually distinctly below those available using conventionalheterogeneous catalyst systems. Defects distributed randomly along thepolymer chain cause metallocene polypropylenes, which generally havemelting points between 135 and 150° C., to be less capable ofcrystallizing. The use of metallocenes as catalysts for the synthesis ofpolypropylenes also permits better stereospecific polymerization, i.e.the tacticity of the polypropylenes and hence their properties areeasier to control. Polypropylenes catalysed using metallocenes have anarrower molar mass distribution, i.e. they contain virtually no heptanesolubles any more.

In addition to the type of catalyst used in their synthesis,polypropylenes can also be distinguished according to the spatialarrangement of the side groups of the carbon main chain. There isisotactic polypropylene, atactic polypropylene and syndiotacticpolypropylene, although these forms can also occur in mixtures. Theinsecticide-containing polyolefin material to be used according to thepresent invention preferably utilizes polypropylene having apredominantly isotactic structure.

Polypropylenes can be further distinguished according to theirrespective areas of use. The properties of the polymers are specificallyoptimized inter alia for the requirements in injection moulding, inextrusion, in blow moulding, in pressing, in calendering and in meltspinning. The insecticide-containing polymeric material of the presentinvention preferably utilizes polypropylenes intended for themelt-spinning process to produce filaments, fibres and spunbondeds.Particular preference is given to using polypropylene useful for theproduction of multifilaments having a low linear density of 50 to 150denier. These are for example polymers bearing the brand names Metocene®and Moplen® (from LyondellBasell, Netherlands), Repol® (RelianceIndustries Limited, India), Yuplen® (SK corporation, South Korea),Seetec® (LG Chemical. South Korea) and Achieve® (ExxonMobile ChemicalCompany, USA). Particular preference is given to metallocene-catalysedpolypropylenes, for example Metocene® HM562S, melting temperature 145°C. (from LyondellBasell, Netherlands) and Achieve® 3845 (ExxonMobileChemical Company, USA).

The polymeric materials used can be produced with the addition ofadditives which are incorporated into the polymer to stabilize orimprove its processing properties. Suitable additives are for examplealkylated monophenols, alkylthiomethyl phenols, hydroquinones,tocopherols, hydroxylated thiodiphenyl ethers, alkylidenebisphenols, O-,N- and S-benzyl compounds, hydroxybenzylated malonates, aromatichydroxybenzyl compounds, triazine compounds, acylaminophenols, esters ofβ-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid with mono- orpolyhydric alcohols, esters ofβ-(5-tert-butyl-4-hydroxy-3-methylphenyl)propionic acid with mono- orpolyhydric alcohols, esters ofβ-(3,5-dicyclohexyl-4-hydroxyphenyl)propionic acid with mono- orpolyhydric alcohols, esters of 3,5-di-tert-butyl-4-hydroxyphenyl aceticacid with mono- or polyhydric alcohols, amides ofβ-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid, ascorbic acid(Vitamin C) and aminic antioxidants. It is likewise possible to usethiosynergists, secondary antioxidants, phosphites and phosphonites.

It is likewise possible to produce the polymeric materials used by usingmetal deactivators, peroxide scavengers, basic costabilizers, nucleatingagents, plasticizers, lubricants, emulsifiers, pigments, viscositymodifiers, catalysts, flow control agents, optical brighteners,flameproofing agents, antistatic agents and blowing agents,benzofuranones and indolinones, fluorescent plasticizers, mould releaseagents, flame-retardant additives, antistatic agents such as sulphonatesalts, pigments and also organic and inorganic dyes and also compoundscontaining epoxy groups or anhydride groups.

To produce the fabric of the present invention, first the polymericmaterial, preferably polypropylene, an insecticidally active ingredientand likewise a UV stabilizer and optionally further insecticides oradditives are melted together or separately at temperatures between 120and 250° C., preferably 150 and 230° C., and subsequently the coolingand solidifying of the polymeric mixture takes place and also thesubdivision of the latter into pellets.

In addition to insecticides, it is optionally possible (and preferable)to use UV stabilizers (i.e. UV absorbers and/or light stabilizers) in anamount of 0.01% to 15% by weight, preferably 0.03% to 8% by weight,based on the total mass of the composition of the insecticide-containingpolymeric material. UV absorbers and/or light stabilizers useful forcarrying out the process are for example2-(2′-hydroxyphenyl)benzotriazoles, 2-hydroxybenzophenones, esters ofsubstituted and unsubstituted benzoic acids, acrylates, nickelcompounds, sterically hindered amines, oxamides,2-(2-hydroxyphenyl)-1,3,5-triazines and also mixtures thereof.Preferably no sterically unhindered amines are used as UV stabilizers,but 2-(2′-hydroxyphenyl)benzotriazoles, 2-hydroxybenzophenones, estersof substituted and unsubstituted benzoic acids, acrylates, nickelcompounds, oxamides, 2-(2-hydroxyphenyl)-1,3,5-triazines and alsomixtures thereof are used. Particular preference is given to triazinecompounds and butrimezole. Very particular preference is given tophenol, 2-(2H-benzotriazol-2-yl)-6-dodecyl-4-methyl-, branched andlinear (CAS 125304-04-3) and2-(5-chloro-2H-benzotriazol-2-yl)-6-(1,1-dimethylethyl)-4-methylphenol(CAS 3896-11-5).

The polymaterial to be used is for example melted in a single-screwextruder, a twin-screw extruder, a multi-screw extruder or a co-kneader.

The single-screw extruder used can be for example a smooth or groovedbarrel extruder or a Transfermix. A grooved barrel extruder ispreferred.

Twin-screw extruders may be co- or counter-rotating. Twin-screwextruders may further be close-meshing or non-intermeshing. Preferenceis given to a close-meshing corotating configuration.

Multi-screw extruders have at least three screws, preferably four totwelve. The screws may each be arranged to form close-meshing pairs, inwhich case the screw pairs can be arranged tangentially andcounter-rotating relative to each other. The screws of a multi-screwextruder can further be all corotating, in which case each screwintermeshes in two neighbouring screws. A special form of multi-screwextruder is the planetary roll extruder wherein a driven central spindledrives freely revolving planetary spindles which in turn circulate in afixed housing. The central spindle, the planetary spindles and thehousings have toothed-wheel intermeshing.

The process of the present invention is particularly preferably carriedout using a close-meshing corotating twin-screw extruder.

The construction of the extruder screw is adapted to the respectiveapplication scenario.

Room temperature solid insecticides, optionally UV stabilizers and otheradditives are in a preferred embodiment metered together with thestarting polymer pellets into the feed zone of the extruder. In anotherpreferred embodiment, room temperature solid insecticides, UVstabilizers and other additives are melted and metered in liquid form.The extruder housings are temperature controlled to 4 to 250° C. Theextruder housing at the feed zone of the extruder is preferably cooledto 4 to 50° C. The remaining extruder housings are preferablytemperature controlled to 100 to 250° C. and more preferably to 140 to250° C. In the extruder, the polymer and, depending on the meltingpoint, the insecticide as well and also the UV stabilizer are melted andmixed. The mixture is extruded through a hole die and pelletized. Theadditives may also comprise further inorganic or organic fillers such asfor example organic pigments, titanium dioxide, carbon black or talcum.

The residence times in which the polymer is liquid during melting andmixing are between 3 and 300 seconds, preferably between 5 and 120seconds and more preferably between 8 and 30 seconds.

The mixing of the insecticide, optionally of the UV stabilizer and ofother additives with the molten polymer can take place in the sameapparatus in which the melting of the polymer takes place, or in afurther apparatus. All the abovementioned extruders are suitable for themixing. A further possibility is to mix the insecticide and, whereappropriate, the additives with the polymer in a static mixer. Themixing is preferably carried out with a static mixer.

When the insecticide or the additives is added in liquid form, it isgenerally melted and intermediately stored in an initial charge vessel,from which it is then conveyed into the mixing apparatus. The conveyingcan be effected for example via a pump or via an increased admissionpressure. The temperature of the initial charge vessel is chosen suchthat the insecticide is stable and the viscosity of the insecticide issufficiently small to ensure good pumpability. It is advantageous inthis case to heat the initial charge vessel, the pump and alt lines. Themetering into the mixing apparatus preferably proceeds via a needlevalve. The metered amount of insecticide is preferably measured by asuitable mass flow rate meter, for example according to the Coriolisprinciple or according to the heated wire principle, and closed-loopcontrolled to small deviations via the pump or a valve.

Room temperature liquid insecticides are added to the already moltenpolymer in a processing zone of the extruder via a needle valve.Depending on the viscosity and melting point of the insecticide, theinsecticides, UV stabilizers and other additives or their mixture areheated for this.

After mixing, a preferred embodiment comprises cooling and solidifyingof the polymeric materials and also subdivision into pellets. This canbe accomplished for example using the common strand pelletizationprocess wherein one or more dies extrude continuous strands which arethen air or water cooled to solidify them and subsequently comminuted tothe desired size in a pelletizer. Underwater pelletization is a furthermethod, the melt emerging from the die underwater, being cut there andby a circulating blade and subsequently water cooled, thereafterscreened off and dried. A further method is water ring pelletizationwhere the polymer is cut in the liquid-melt state in air and thereafterwhizzed by centrifugal forces in a rotating water ring to cool.Particular preference is given to the method of underwater pelletizationand to the strand pelletization process.

In one embodiment of the process of the present invention, onlypolymeric material produced by the mixing operation is led to asubsequent processing operation. The amount of insecticide in the simplemixing operation is in the range from 0.05% to 15% by weight, preferablyin the range from 0.2% to 10% by weight and more preferably in the rangefrom 0.4% to 8% by weight, based on the total mass.

In a further embodiment, a polymeric material having an increasedconcentration of insecticidally active ingredient is produced in pelletform (known as a masterbatch) and fed to a subsequent processingoperation in a mixture with untreated polymer. In this case, theconcentration of insecticide in the masterbatch polymeric material ofthe present invention is increased, preferably to a concentrationbetween 3 to 20% by weight and more preferably 5% to 15% by weight basedon the total mass.

A further embodiment comprises a first step of producing the polymericmaterial of the present invention as a masterbatch which thereafter, bymelting and mixing with untreated polymer and possible furtheradditives, is again further processed into a polymeric material of thepresent invention, which is generated in the form of pellets.

The subsequent processing operation may comprise for example theresulting pellets of the polymeric material of the present inventionbeing processed in a processing step into shaped articles such as forexample foils, air-cushioning materials, films, profiles, sheets, wires,threads, tapes, cable and pipe linings, casings for electricalinstruments (for example in switchboxes, aircraft, refrigerators, etc.).Preference is given to producing foils in an extrusion operation. Thesefoils can be produced to have one or more layers. A person skilled inthe art knows methods whereby multilayered foils can be produced. Theseinclude for example coextrusion or lamination. Preference is given to amultilayered foil consisting of one layer of material according to thepresent invention and also of one or more layers of another material.These other materials can be for example polyethylene (HDPE, LDPE,LLDPE) or polyethylene copolymers, polypropylene, adhesion promoterssuch as for example ethylene-vinyl acetate copolymer, polyamide,polycarbonate, polyvinyl chloride, polystyrene, polyesters such as forexample polyethylene terephthalate or polybutylene terephthalate,cellophane, polylactide, cellulose acetate or blends thereof. Thesepolymers can be present in pure form or as blends and may containadditives and further inorganic or organic fillers such as for exampleorganic pigments, titanium dioxide, carbon black or talcum.

It is particularly preferable for the subsequent processing operation toconsist in further processing the insecticide-containing polymericmaterial in a subsequent, spinning operation to form fibres, yarns,filaments or threads.

Suitable insecticidally active ingredients for the fabric of the presentinvention are insecticidally active ingredients from the classes of theorganophosphates, pyrethroids, neonicotinoids and carbamates.

Organophosphates include for example acephate, azamethiphos, azinphos(-methyl, -ethyl), bromophos-ethyl, bromfenvinfos (-methyl),butathiofos, cadusafos, carbophenothion, chlorethoxyfos,chlorfenvinphos, chlormephos, chlorpyrifos(-methyl/-ethyl), coumaphos,cyanofenphos, cyanophos, chlorfenvinphos, demeton-S-methyl,demeton-S-methylsulphon, dialifos, diazinon, dichlofenthion,dichlorvos/DDVP, dicrotophos, dimethoate, dimethylvinphos,dioxabenzofos, disulfoton, EPN, ethion, ethoprophos, etrimfos, famphur,fenamiphos, fenitrothion, fensulfothion, fenthion, flupyrazofos,fonofos, formothion, fosmethilan, fosthiazate, heptenophos, iodofenphos,iprobenfos, isazofos, isofenphos, isopropyl O-salicylate, isoxathion,malathion, mecarbam, methacrifos, methamidophos, methidathion,mevinphos, monocrotophos, naled, omethoate, oxydemeton-methyl, parathion(-methyl/-ethyl), phenthoate, phorate, phosalone, phosmet, phosphamidon,phosphocarb, phoxim, pirimiphos (-methyl/-ethyl), profenofos, propaphos,propetamphos, prothiofos, prothoate, pyraclofos, pyridaphenthion,pyridathion, quinalphos, sebufos, sulfotep, sulprofos, tebupirimfos,temephos, terbufos, tetrachlorvinphos, thiometon, triazophos, trielorfonand vamidothion.

The pyrethroids include for example acrinathrin, allethrin (d-cis-trans,d-trans), beta-cyfluthrin, bifenthrin, bioallethrin,bioallethrin-S-cyclopentyl-isomer, bioethanomethrin, biopermethrin,bioresmethrin, chlovaporthrin, cis-Cypermethrin, cis-Resmethrin,cis-Permethrin, clocythrin, cycloprothrin, cyfluthrin, cyhalothrin,cypermethrin (alpha-, beta-, theta-, zeta-), cyphenothrin, deltamethrin,empenthrin (1R-isomer), esfenvalerate, etofenprox, fenfluthrin,fenpropathrin, fenpyrithrin, fenvalerate, flubrocythrinate,flucythrinate, flufenprox, flumethrin, fluvalinate, fubfenprox,gamma-cyhalothrin, imiprothrin, kadethrin, lambda-cyhalothrin,metofluthrin, permethrin (cis-, trans-), phenothrin (1R-trans isomer),prallethrin, profluthrin, protrifenbute, pyresmethrin, resmethrin, RU15525, silafluofen, tau-Fluvalinate, tefluthrin, terallethrin,tetramethrin (-1R-isomer), tralomethrin, transfluthrin, ZXI 8901 andpyrethrin (pyrethrum). Preference according to the present invention isgiven to beta-cyfluthrin, bifenthrin, cyfluthrin, deltamethrin andtransfluthrin. Particular preference according to the present inventionis given to cyfluthrin, deltamethrin, permethrin (cis-, trans-) andtransfluthrin.

The neonicotinoids include for example acetamiprid, clothianidin,dinotefuran, imidacloprid, nitenpyram, nithiazine, thiacloprid andthiamethoxam. Preference according to the present invention is given toimidacloprid and clothianidin.

The carbamates include for example alanycarb, aldicarb, aldoxycarb,allyxycarb, aminocarb, bendiocarb, benfuracarb, bufencarb, butacarb,butocarboxim, butoxycarboxim, carbaryl, carbo-furan, carbosulfan,cloethocarb, dimetilan, ethiofencarb, fenobucarb, fenothiocarb,formetanate, furathiocarb, isoprocarb, metam-sodium, methiocarb,methomyl, metolcarb, oxamyl, pirimicarb, promecarb, propoxur,thiodicarb, thiofanox, trimethacarb, XMC, xylylcarb and triazamate.Preference according to the present invention is given to bendiocarb andcarbaryl.

Likewise suitable insecticides are for example DDT, indoxacarb,nicotine, bensultap, cartap, spinosad, camphechlor, chlordane,endosulfan, gamma-HCH, HCH, heptachlor, lindane, methoxychlor,acetoprole, ethiprole, fipronil, pyrafluprole, pyriprole, vaniliprole,avermectin, emamectin, emamectin-benzoate, ivermectin, milbemycin,diofenolan, epofenonane, fenoxycarb, hydroprene, kinoprene, methoprene,pyriproxifen, triprene, chromafenozide, halofenozide, methoxyfenozide,tebufenozide, bistrifluron, chlofluazuron, diflubenzuron, fluazuron,flucycloxuron, flufenoxuron, hexaflumuron, lufenuron, novaluron,noviflumuron, penfluron, teflubenzuron, triflumuron, buprofezin,cyromazine, diafenthiuron, azocyclotin, cyhexatin, fenbutatin-oxide,chlorfenapyr, binapacyrl, dinobuton, dinocap, DNOC, fenazaquin,fenpyroximate, pyrimidifen, pyridaben, tebufenpyrad, tolfenpyrad,hydramethylnon, dicofol, rotenone, acequinocyl, fluacrypyrim, Bacillusthuringiensis strains, spirodiclofen, spiromesifen, spirotetramat,3-(2,5-dimethylphenyl)-8-methoxy-2-oxo-1-azaspiro[4.5]dec-3-en-4-ylethyl carbonate (alias: carbonic acid,3-(2,5-dimethylphenyl)-8-methoxy-2-oxo-1-azaspiro[4.5]dec-3-en-4-ylethyl ester, CAS-Reg.-No.: 382608-10-8), flonicamid, amitraz,propargite, flubendiamide, rynoxapyr, chloranthraniliprol, thiocyclamhydrogen oxalate, thiosultap-sodium, azadirachtin, Bacillus spec,Beauveria spec, Codlemone, Metarrhizium spec, Paecilomyces spec,Thuringiensin, Verticiliium spec, aluminium phosphid, methylbromide,sulfurylfluorid, cryolite, flonicamid, pymetrozine, clofentezine,etoxazole, hexythiazox, amidoflumet, benclothiaz, benzoximate,bifenazate, bromopropylate, buprofezin, chinomethionat, chlordimeform,chlorobenzilate, chloropicrin, clothiazoben, cycloprene, cyflumetofen,dicyclanil, fenoxacrim, fentrifanil, flubenzimine, flufenerim,flutenzin, gossyplure, hydramethylnone, japonilure, metoxadiazone,petroleum, piperonylbutoxid, kaliumoleat, pyridalyl, sulfluramid,tetradifon, tetrasul, triarathene and verbutin.

The insecticides mentioned can be used individually or in a mixture.

Preferred insecticides are beta-cyfluthrin, permethrin (cis-, trans-),deltamethrin, transfluthrin, bendiocarb, clothianidin, imidacloprid,thiacloprid, ethiprol, fipronil, rynoxapyr, chlorpyriphosmethyl,chlorfenapyr. Particular preference is given to deltamethrin,beta-cyfluthrin, transfluthrin, bendiocarb, clothianidin, ethiprol andrynoxapyr, and mixtures of the abovementioned insecticides. Theinsecticide used most preferably is deltamethrin.

The concentration of the insecticidally active ingredient in thepolymeric material can be varied within a relatively wide concentrationrange from, for example 0.05% to 15% by weight, preferably 0.2% to 10%by weight, more preferably 0.4% to 8% by weight. The concentration shallbe chosen according to the field of application such that therequirements concerning insecticidal efficacy, durability and toxicityare met. Adapting the properties of the material can also beaccomplished by mixing insecticides in the polymeric material by theblending of materials according to the present invention which containdifferent insecticides, or by using materials according to the presentinvention which contain different insecticides which are used incombination with each other, for example as mosaic nets. Custom-tailoredtextile fabrics are obtainable in this way.

In the production of filaments, fibres, threads and yarns, theinsecticide-containing polymeric material is initially melted, formedinto spun threads and cooled, the spun threads obtained are led througha drawing system and drawn and then optionally the setting of thefilaments, fibres, threads and yarns takes place.

In this process, a spin finish is preferably used during the spinningoperation.

The threads or filaments are produced, after the mixing operation, bymelt spinning as described for example in DE-A 41 36 694 (page 2, lines27-38, page 5, line 45-page 6, line 23) or DE-A 10 2005 054 653([0002]). In this process, the insecticidal polymer produced is meltedin a single-screw extruder and forced with the aid of a gear pumpthrough a die plate. The die plate is preceded by a filter pack. Thepolymer strands emerging from the die plate are subjected to high-speeddrawing, spin finishing and winding up.

The melt-spinning process comprises the steps of:

-   -   1. preparing the spinning melt    -   2. melt spinning    -   3. cooling    -   4. spin finishing    -   5. drawing    -   6. aftertreating

The fibres are produced from the molten polymeric material of thepresent invention using the known melt-spinning processes. Preference isgiven to processes for producing monofilament fibres, multifilamentfibres, fibrous non woven webs, hollow fibres, staple fibres,multicomponent fibres and matrix-embedded microfibers. The production ofmultifilament fibres is particularly preferred.

In step (1), the insecticide-containing polymeric material, produced bythe mixing operation, is melted at temperatures of at least 10° C. belowthe decomposition temperature and at least 5° C. above the melting pointof the polymeric material and conveyed without cooling to thespinnerette die pack. The polymeric material is preferably melted andspun at a temperature below 250° C., more preferably below 235° C.

Fibre production can be carried oat in one stage by the polymericmaterial being fed to the spinning operation directly after mixing, inmolten form. It is similarly possible to carry out a two-stage processwherein the previously produced pellets composed of the above-describedpolymeric material are melted in a conveyor extruder or in a heatableflask and conveyed to the spin pack.

In a preferred embodiment, the insecticide-containing polymeric materialis fed to the spinning operation directly after mixing, in molten form.

It is particularly preferable for the insecticide-containing masterbatchpolymeric material, having an increased insecticide concentration, to bemixed with purely polymer material in the course of the spinningoperation. It is preferable for the polymeric material used to be onlypolypropylene which has been prepared with metallocenes as catalyst. Themixing can be effected in different ways. In one embodiment, theinsecticide-containing polymeric material and the additional polymericmaterial are fed via two separate metering assemblies to thesingle-screw extruder in which the materials are melted. In a furtherembodiment, the two polymeric materials are mixed prior to addition intothe single-screw extruder and then supplied to the extruder in the formof a premix. In a further embodiment, the insecticide-containing polymerand the unloaded polymeric material are melted in two separate extrudersand these two streams of melt are subsequently mixed with each other.

The spinnerette die pack consists of a known construction. Thespinnerette die plate can have one to several thousand die holes havinghole diameters customary for fibre production. After the spinnerette diepack, the spun threads pass through a cooling sector, are spin finishedand are wound up or deposited in cans. The cooling medium used is aliquid or a gas. When it is a liquid, water is used. Dry cooling sectorstake the form of quenching chambers in which the spun threads are cooleddown with cold air, nitrogen or carbon dioxide being used as coolinggas.

A spin finish is applied to the fibres in the course of the spinningoperation. Application of the spin finish modifies the surfaceproperties of the fibres. The spin finish inter alia reduces thefriction between metal and thread and between thread and thread, andalso reduces the antistatic charging of the fibres. The application of aspin finish is necessary to carry out the melt-spinning operation.Without an appropriate spin finish, the winding and unwinding andfurther processing of filament yarns is not possible. A person skilledin the art knows how to adapt a spin finish for this purpose. Spinfinishes are also known to a person skilled in the art. The amount ofthe applied nonaqueous constituents of the spin finish is in the rangefrom 0.1% to 2.0% by weight and preferably in the range from 0.5% to1.5% based on the total mass of the fibre.

The spin finish can be applied at the point of exit from or entry to thefibre production line, the winding/take-off machine, the rewindingmachine and/or the quench chamber.

The spin finish, or to be more precise the mixture of spin, finish andwater, can be applied to the fibre in various ways. In principle, it canbe applied by spraying, dipping, rolls, rods and pins.

The spin finish can be meteringly added in one, two or in a plurality ofstages.

The wound-up or deposited spun threads can then be led through a drawingsystem and drawn and wound up as flat filament, or optionally becrimped, set or cut into staple fibres.

Preferably, the spinning and drawing operations are carried out in onesystem without intermediate winding up of the undrawn filaments.Suitable drawing systems are draw-twist or draw-wind machines for flatmultifilaments, compact monofil spin-draw systems for monofilaments,draw production lines and compact spin-draw systems for staple fibres.The drawing systems can be equipped with beatable or partly non-heatablegodets or draw rolls, and also guide rollers, further with steam,hot-air and infrared ducts, coating devices, crimping units, dryers,cutting systems and other units. The drawing operation can be followedby any known finishing measure, such as the application of a coating forexample.

Setting the filaments or fibres is usually carried out on these systemsafter the drawing step.

The multifilaments spun at high speed can be draw-textured on machinesknown for this purpose, and similarly the drawn multifilaments can betextured.

Multifilaments preferred according to the present invention have 1 to100 filaments, more preferably 5 to 75 filaments and most preferably 10to 60 filaments.

According to the present invention, fibres having a linear density of1000 to 10 denier, preferably 500 to 20 denier and more preferably 200to 50 denier are used.

The threads, yarns, fibres or filaments thus produced can subsequentlybe further processed into any desired products such as for exampletextile fabrics. Preference is given for example to wovens, braids,knits, felts or nonwovens. Particular preference is given to netlikefabrics such as sleeping nets for example.

The production of wovens and braids is effected by means of two threadsystems (warp and weft) crossing each other at right angles. A knittedfabric can be produced from one thread (one-thread knit) or beconstructed from two or more threads (warp-thread knit) according to thewarp-thread technique. These fabrics of the present invention areproduced on loop-forming or -drawing machines. It is further possible touse short threads or thread pieces to produce felts or nonwovens.

To produce the netlike fabrics of the present invention by means ofloop-forming and -drawing processes, it is necessary to produce aso-called warp beam. The polymeric threads are wound in equal length ina parallel arrangement on a bobbin, the so-called warp beam.

To render the polymeric threads more lubricious and robust duringprocessing into the textile fabric of the present invention, the threadsare frequently sized, i.e. coated with a protective film of starch orsynthetic sizes. Sizing can be effected using a winding oil which isapplied during warp-beam production in order to improve the windingproperties during warp-beam production and to reduce thread-on-threadfriction and also friction between metal and thread. Reducing frictionis important not only for warp-beam production but also for thesubsequent loop-forming operation.

Prior to further treatment (for example bleaching and dyeing), textilefabrics composed of manufactured fibres are generally washed, since themanufactured fibres contain small amounts of additives at the fibresurface. These additives comprise more particularly the above-describedspin finishes, but other additives such as possibly applied sizes arealso removed in the process. This washing operation may be carried outin various ways generally known to a person skilled in the art. In someprocesses, the washing liquor is agitated, in other processes thetextile fabric moves through the quiescent washing liquor. Possibleprocesses are pulsed washers, jet washers, washing on sieve drums,pad-mangles and also vacuum processes. Continuous processes arepreferred on an industrial scale.

In the case of polypropylene and polyethylene fibres, this operation isnot carried out in the prior art processes since textile fabricscomposed of these polymers cannot be dyed with a dyebath. This holdsmore particularly for the production of mosquito nets, since in thiscase the textile fabric is not subjected to any further finishingoperation apart from heat setting.

Surprisingly, however, the washing of the netlike fabric of the presentinvention with water and a detergent prior to the heat-setting step hasbeen found to have a positive effect on the loss of insecticide duringwashing according to the WHOPES guideline. All the washing processesdescribed above (i.e. pulsed washers, jet washers, washing on sievedrums, pad-mangles and also vacuum processes) can be used for thiswashing operation.

The fabric thus produced has very elastic properties frequently and isnot form stable. In this form, it is more particularly unsuitable forthe production of mosquito nets, since this use has specificrequirements in terms of shrinkage determined to DIN EN ISO 5077.Therefore, it is preferred to carry out a heat-setting operation. Heatsetting can be carried out with hot water, saturated steam or hot air,or in a dry atmosphere. Preference is given to carrying out heat settingin a normal atmosphere without additional supply of water or steam. Heatsetting is preferably carried out using a continuous process in whichthe textile fabric is fixed on a stenter and led through an oven on astenter. This oven is preferably subdivided into two or more heatingzones which can be individually temperature controlled. During thethermal treatment, the textile fabric can be concurrently subjected tomechanical loading to a varying degree by stretching. This is done bymoving the two sides of the stenter apart in the setting oven until thedesired width is reached for the formed-loop knit.

The temperature to heat-set the netlike fabric of the present inventionis chosen 20° C., preferably 10° C., below the melting temperature ofthe polymer. Surprisingly, heat setting at a few degrees below themelting temperature of the polymer was found to lead to a reduction inthe loss of insecticide during a wash in soapy water.

In addition to the abovementioned netlike fabrics, threads, yarns,fibres or filaments can also be subjected to the washing operation ofthe present invention and the heat setting of the present invention.These materials also subsequently exhibit the technical effectsdescribed in the present invention.

In addition to the surprisingly found effect of the setting temperatureon the release of the insecticide from the material of the presentinvention during washing in accordance with WHOPES directive in soapywater, the setting temperature and the duration of the setting operationwhich is determined via the speed at which the formed-loop knit is ledthrough the setting oven lead to alteration of the crystal structure inthe polymer. The crystal structure can be determined using DSCmeasurements (DSC=Differential Scanning Calorimetry (dynamicdifferential calorimetry)). Differential scanning calorimetry is ameasurement method known to a person skilled in the art for determiningthe crystallinity of polymers. This method determines the amount of heatwhich needs to be applied for a physical or chemical conversion of asubstance. A description of the method can be found inter alia in“Praxis der Thermischen Analyse von Kunststoffen”, Ehrenstein, Riedel,Trawiel, Carl Hanser Verlag, Munich 2003. Upon measurement at a heatingrate of 10 K/min, the materials of the present invention only have a lowproportion of crystal structures that melt above the preferred settingtemperature during the DSC measurement under customary conditions.

For example, to produce the netlike fabric of the present invention,consisting of the polypropylene HM 562 S from Basell, the duration hasto be chosen such that, during a customary DSC measurement at a heatingrate of 10 K/min, the amount of crystal structures in the material ofthe present invention that melts above 140° C. is more than 62 J/g andpreferably more than 65 J/g.

The insecticide-containing fabrics of the present invention can besuccessfully used for killing harmful or nuisance arthropods, moreparticularly arachnids and insects. The netlike fabrics of the presentinvention are preferably used for producing sleeping nets for protectionagainst mosquitoes.

Arachnids include mites (e.g. Sarcoptes scabiei, Dermatophagoidespteronys-sinus, Dermatophagoides farinae, Dermanyssus gallinae, Aearnssiro) and ticks (e.g. Ixodes ricinus, Ixodes seapularis, Argas reflexus,Ornithodorus moubata, Boophilius microplus, Amblyomma hebracum,Rhipicephaius sanguineus).

Sucking insects include essentially the mosquitoes (e.g. Aedes aegypti,Aedes albopictus, Aedes vexans, Culex quinquefasciatus, Culex tarsalis,Anopheles gambiae, Anopheles albimanus, Anopheles stephensi, Mansoniatitillans), sand flies (e.g. Phlebotomus papatasii), gnats (e.g.Culicoides furens), black flies (e.g. Simulium damnosum), bitinghouseflies (e.g. Sto-moxys calcitraus), Tsetse flies (e.g. Glossinamorsitans morsitans), horseflies (e.g. Taba-nus nigrovittatus,Haematopota pluvialis, Chrysops caecutiens), common houseflies (e.g.Musca dornestica, Musca autumnalis, Musca vetustissima, Fanniacanicularis), flesh flies (e.g. Sarcophaga camaria), myiasis-causingflies (e.g. Lucilia cuprina, Chrysomyia chloio-pyga, Hypoderma bovis,Hypoderma lineatum, Dermatobia hominis, Oestrus ovis, Gaste-rophilusintestinalis, Cochliomyia hominivorax), bugs (e.g. Cimex lectularius,Rhodnius prolixus, Triatoma infestans), lice (e.g. Pedieulus humanis,Haematopinus suis, Damalina ovis), fleas (e.g. Pulex irritans,Xenopsylla cheopis, Ctenocephalides canis, Ctenocephali-des felis) andsand fleas (Tunga penetrans).

Biting insects include essentially cockroaches (e.g. Blattetlagermanica, Periplaneta americana, Blatta orientalis, Supellalongipalpa), beetles (e.g. Sitiophilus granarius, Tenebrio molitor,Derrnestes lardarius, Stegobium paniceum, Anobium punctatum, Hylotrupesbajulus), termites (e.g. Reticulitermes lucifugus), ants (e.g. Lasiusniger, Monomorium pharaonis), wasps (e.g. Vespula germanica) and larvaeof moths (e.g. Ephestia elutella, Ephestia cautella, Plodiainterpunctella, Hofmannophila pseudospretella, Tineola bisselliella,Tinea pellionella, Trichophaga tapetzella).

The materials of the present invention are preferably used againstinsects, particularly of the order Diptera and even more preferablyagainst the suborder Nematocera.

The present invention likewise provides for the use of the netlikefabric of the present invention in the manufacture of sleeping nets.

The present invention also provides for sleeping nets, mosquito nets,wovens, braids, knits, felts, nonwovens which consist of (or at leastcontain) a netlike fabric according to the present invention. Mosquitonets and sleeping nets are preferred according to the present invention.

The present invention further provides spun threads based on aninsecticide-containing polymeric material, characterized in that thespun threads are obtained by the following steps:

a) melting the polymer to be used and one or more insecticidally activeingredients together or separately at temperatures between 120 and 250°C.,

b) forming the melt of step a) into spun threads and cooling,

c) optionally leading the spun threads formed in step b) through adrawing system and drawing and then optionally setting the threads,

d) subjecting the spun threads to a heat-setting operation wherein thetemperature for the heat-setting operation is chosen to be 20° C. belowthe melting temperature of the polymer to be used.

The polymer used is preferably polypropylene produced using metallocenesas a catalyst.

A spin finish is preferably used in the production of the spun threadsin step b).

In a further preferred embodiment, the heat setting in step d) of theproduction of the spun threads is preceded, by a washing step. Water anda detergent is preferably used for this. The heat setting is preferablycarried out in a dry atmosphere. Further preferred methods of productionare described above.

The spun threads according to the present invention can also be presentin the form of threads, yarns, fibres or filaments and further processedin any desired manner. Preferably, the spun threads are knitted to formnetlike fabrics in a further step e).

The present invention also provides threads, yarns, fibres, filaments,netlike fabrics, preferably sleeping nets, mosquito nets, wovens,braids, knits, felts, nonwovens which consist of (or at least contain)the spun threads according to the present invention.

The present invention further provides netlike fabrics based on aninsecticide-containing polymeric material, characterized in that thenetlike fabrics are produced by the following steps:

a) melting the polymer to be used and one or more insecticidally activeingredients together or separately at temperatures between 120 and 250°C.,

b) forming the melt of step a) into spun threads and cooling,

c) optionally leading the spun threads formed in step b) through adrawing system and drawing and then optionally setting out the threads,

d) knitting the spun threads to form a netlike fabric,

e) subjecting the netlike fabrics to a heat-setting operation whereinthe temperature for the heat-setting operation is chosen to be 20° C.below the melting temperature of the polymer to be used.

The polymer used is preferably polypropylene produced using metallocenesas a catalyst.

A spin finish is preferably used in the production of the netlikefabrics in step b).

In a further preferred embodiment, the heat setting in step d) of theproduction of the net like fabrics is preceded by a washing step. Waterand a detergent is preferably used for this. The heat setting ispreferably carried out in a dry atmosphere. Further preferred methods ofproduction are described above.

The present invention also provides sleeping nets, mosquito nets,wovens, braids, knits, felts, nonwovens consisting of (or at leastcontaining) a netlike fabric produced according to the process describedabove.

Netlike fabrics according to the present invention preferably have aminimum of 23 complete holes/cm² and on average between 23 and 29complete holes/cm².

EXAMPLES Test Methods Biology

Test Insects

Female malaria mosquitoes (Anopheles gambiae, sensitive Kisumu strain),fed with sugared water only.

Three-Minute Exposure (Cone Test)

The tests were carried out using WHO standard cones with an exposuretime of 3 minutes on part-samples. The net pieces were 30×30 cm in size.In each case, five mosquitoes at a time were placed under one cone andfour cones were used on a part-sample. The same sample was subsequentlytested once more with four cones and once with two cones, i.e. 2.5replications involving altogether 50 mosquitoes.

After exposure, the insects were transferred into plastic cups 10 at atime and the knock-down effect was determined after 60 minutes.Knock-down is the first visible indication of the onset of action, andis characterized in that the insects lose coordination of theirmovements and are no longer able to fly or walk. Thereafter, sugaredwater was likewise administered and mortality determined after 24 hours.After the tests, the average values were computed.

Washing Operation in Accordance with WHOPES Directive

500 ml of deionized water containing 0.2% (w/v) of laundry detergent (LeChat, Henkel, France) were introduced at 30° C. into a 1 liter glassbottle. One piece of net 30×30 cm in size or three pieces of net 15×12cm in size were introduced into the bottle which stood on a horizontalshaker (155 movements per minute) in a water bath at 30° C. Thereafter,the water was poured out of the bottle and the sample was rinsed twicewith 500 ml of water each time for 10 minutes again under shaking.

The net samples were line dried for two hours and thereafteradditionally for at least 24 hours lying on aluminium foil at 27° C. and70-80% relative humidity before renewed washing or an evaluation ofbiological activity.

Analysis of Deltamethrin in Polypropylene

Part A—Sample Preparation:

About 1 g of material of a representative sample (yarn, fabric orpellet) is placed in a 250 ml flask; then approximately 30 ml of xylene(PA quality) are added. The sample material is then dissolved atprecisely 3 minutes in an oil bath at 190° C. under reflux (water-cooledcolumn, 20 cm) and stirring (125 revolutions per minute, magneticstirrer and stirring bar). The oil bath is removed and about 10 ml ofisopropanol (PA quality) are added and the flask is left to cool forabout 5 minutes at room temperature to precipitate the polymer.Thereafter the extract is made up with 30 ml of acetonitrile.

The sample is subsequently filtered off with suction (analytical finer,5 cm diameter) and thereafter the filtrate is passed through a flutedfilter (MN 715, 240 mm). Both filtrations are done by washing with 10-20ml of solvent (acetonitrile) in each case.

Finally, the filtrate is quantitatively transferred into a 100 mlgraduated flask and made up with acetonitrile to the calibration mark.

Part B—Quantitative Determination by HPLC Versus External Standard:

The quantification of deltamethrin in samples of polypropylene extractsis carried out by means of HPLC on an Agilent 1100 instrument equippedwith a binary pumping system. Deltamethrin and the R-alpha isomer arethe target molecules of the analysis. Certified analytical standards areused as reference materials. Separation is carried out under normalphase conditions on a Merck Lichrosorb SI 60 column (5μ particles,dimensions 250×4 mm) at 40° C. column temperature.

The injection volume is 10 μl (sample preparation see Part A above).Separation is effected by means of a solvent mixture of N-heptane andmethyl tertiary-butyl ether (950+50, HPLC quality) at a flow rate of 1ml per minute. The elution time under these conditions is 10 minutes.

UV detection at a wavelength of 230 nm utilizes a diode array detector.The typical retention time under the conditions described is about 6.3minutes for the R-α-isomer and 7.0 minutes for the deltamethrin.

Production of Samples:

The polymeric materials were produced using a corotating close-meshingtwin-screw extruder having a screw diameter of 34 mm and a housinglength of 1200 mm. Extruder housing temperature was 200° C. in all stepsand extruder speed was 160 rpm. The feed zone of the extruder was cooledwith water. The extruder was used to produce a so-called masterbatchhaving a high concentration of deltamethrin. To this end, 10% by weightof technical grade deltamethrin (BCS AG, Monheim Del.), 2% by weight ofTinuvin® 326 FL (BASF (Ciba), Ludwigshafen, Germany) and 88% by weightof polypropylene (Metocen® HM562S, LyondellBasell, Rotterdam,Netherlands) were mixed in the extruder (TK10). All the materials weresupplied in solid form to the feed zone of the extruder. The mixtureemerged from the extruder in the form of strands and the strands werecooled in a water bath. Subsequently, the strands were comminuted bypelletization. The pellets contained about 9.2% by weight ofdeltamethrin.

A second step involved producing threads by diluting about 1.1% byweight of the deltamethrin-containing pellets produced as describedabove with 98.9% by weight of purely polypropylene (Metocen® HM562S orYuplen® H 893S (SK Corporation, Seoul, Korea)). To this end, the pelletswere in each case metered into the feed zone of a single-screw extruderand melted and the two melt streams subsequently combined and mixed. Inthe course of spinning, about 1% by weight of Stantex® 6051 spin finish(Pulcra Chemicals GmbH, Düsseldorf, Germany) was applied to the fibres.The fibres were subsequently drawn and wound up on bobbins. Fibrethickness was 210 dtex and the fibres consisted of 25 filaments. In thesecond step, the fibres were drawn down to a thickness of 110 dtex.Three pairs of godets were used for drawing the fibres. The temperatureof the pairs of godets was 60, 80 and 120° C. The average tenacity ofthe fibres was 4.3 cN/dtex and the residual extension of the fibres was51%.

The two polypropylenes used for dilution differ inter alia in theirmethod of production. Metocen® HM 562S polypropylene was produced usinga metallocene catalyst, while Yuplen® H 893S polypropylene was producedusing a Ziegler-Natta catalyst.

The polypropylene fibres spun were subsequently used to produce theformed-loop knits according to the invention (i.e. the netlike fabricsof the present invention) and the comparative samples. To this end, thefirst step was to produce a warp beam by winding the polypropylenefibres from the individual packages in a parallel arrangement onto onebobbin, the so-called warp beam. These warp beams were subsequently usedin a warp-knitting machine to produce the formed-loop knit.

A portion of the untreated formed-loop knit was subsequently subjectedto a heat-setting operation on a laboratory scale. This was done using aMathis DHe 61599 type laboratory steamer. Prior to heat setting, aportion of the pieces or formed-loop knit was washed once. For 1 to 2net pieces about 35 cm×35 cm in size, 300 ml of 30° C. tap water areadmixed with 0.1% of Tween® 20 (Sigma-Aldrich Chemie GmbH, Munich,Germany) and homogenized. A glass rod is used to stir the net piecestherein for 5 min, which are subsequently wrung out and rinsed for 2×1min with 300 ml of demin water at about 15-20° C. (likewise withstirring). The net pieces are then hung up for at least 1 h to dry.Other pieces of formed-loop knit were subjected to the setting operationin an unwashed state. The setting operation was carried out at differenttemperatures.

The atmosphere in which the heat setting was carried out was alsovaried. The heat setting was carried out in a dry atmosphere or in awater vapour saturated atmosphere.

The samples according to the invention and the comparative samples wereevaluated in respect of their biological activity and their loss ofdeltamethrin. This was followed by the repeated performance of thewashing procedure of the WHOPES protocol and further evaluations of thebiological activity and of the loss of deltamethrin.

Results

1st Example Influence of Spin-Finish Wash-Off on Biological Activity

In this example, the fibres were produced using exclusively Metocen® HM562S polypropylene. That is, the dilution of the masterbatch duringspinning was done with this polymer. The melting point of Metocen® HM562S polymer is 145° C., according to its data sheet. Subsequently, thethreads were used to produce a formed-loop knit in accordance with theoperation described above.

The pieces of formed-loop knit were heat set for 90 seconds in asteam-containing atmosphere at different temperatures. One half of thepieces of formed-loop knit were washed in accordance with theabove-described procedure prior to heat setting in order to remove thespin finish from the fibres, while the other half of the pieces offormed-loop knit were not further treated prior to heat setting. Thespin finish was still present on the threads of these pieces offormed-loop knit.

The pieces of formed-loop knit were initially tested in respect of theirbiological activity in accordance with the above-described procedure.Subsequently, the pieces of formed-loop knit were washed in accordancewith the above-described washing operation to WHOPES directive for 5,10, 15, 20, 25 and 30 times in succession and each thereafter evaluatedin respect of their biological activity.

TABLE 1 Influence of spin finish on biological activity Number ofTemperature washes to Knock-down after 60 min Mortality after 24 h ofheat WHOPES Samples washed Samples Samples washed Samples settingprotocol prior to heat unwashed prior prior to heat unwashed prior [°C.] [-] setting to heat setting setting to heat setting 110 0 100% 100%100% 100% 120 0 100% 100% 100% 100% 130 0 100% 100% 100% 100% 140 0 100%100% 100% 100% 110 5 100% 100% 100% 100% 120 5 100% 100% 100% 100% 130 5100% 100% 100% 100% 140 5 100% 100% 100% 100% 110 10 100%  95%  95%  95%120 10  98%  88%  97%  88% 130 10  98% 100% 100% 100% 140 10 100%  98%100%  98% 110 15  98%  85%  94%  52% 120 15  96%  82%  96%  53% 130 15100%  89%  95%  89% 140 15 100%  91% 100% 100% 110 20 100%  95%  97% 84% 120 20  98%  95% 100%  76% 130 20 100%  63% 100%  37% 140 20 100% 90% 100%  95% 110 25 100%  88% 100%  80% 120 25  95%  80%  95%  59% 13025  98%  80%  93%  78% 140 25 100%  88%  98%  93% 110 30  95%  85% 100% 89% 120 30  96%  70%  96%  54% 130 30 100%  83% 100%  90% 140 30 100% 93%  95%  98%

The results show that washing the spin finish off prior to heat settingachieves a significantly better biological effect after 15 washes toWHOPES directive.

The samples washed prior to heat setting display a relationship betweenthe temperature chosen for the heat setting and the biological activity.The closer the temperature to the melting point of the polymer, thehigher the biological effect.

The temperature at heat setting must accordingly be at most 20° C. andpreferably at most 10° C. below the melting temperature of the polymerin order that a maximum biological activity is achieved.

2nd Example Effect of Spin-Finish Wash-Off on Deltamethrin Loss

Example 2 used the same formed-loop knits whose production was describedin Example 1. The samples were investigated in respect of theirdeltamethrin content according to the procedure described above.

TABLE 2 Loss of deltamethrin Number of Temperature washes toDeltamethrin content Retention index of heat WHOPES Samples washedSamples Samples washed Samples setting protocol prior to heat unwashedprior prior to heat unwashed prior [° C.] [-] setting to heat settingsetting to heat setting 110 0 100%  100%  120 0 100%  100%  130 0 100% 100%  140 0 100%  100%  110 5 64% 32% 91.4% 79.4% 120 5 69% 38% 92.8%82.3% 130 5 79% 51% 95.3% 87.4% 140 5 82% 34% 96.0% 80.4% 110 10 53% 26%93.8% 87.2% 120 10 57% 30% 94.5% 88.7% 130 10 63% 39% 95.5% 91.1% 140 1084% 54% 98.2% 94.0% 110 15 52% 22% 95.8% 90.4% 120 15 59% 30% 96.5%92.3% 130 15 61% 34% 96.8% 93.0% 140 15 79% 50% 98.5% 95.4% 110 30 43%23% 97.2% 95.2% 120 30 49% 23% 97.6% 95.2% 130 30 53% 28% 97.9% 95.8%140 30 63% 39% 98.5% 96.9%

The deltamethrin content after heat setting was set equal to 100% andthe pieces of formed-loop knit were subsequently analysed for theirdeltamethrin content after 5, 10, 15 and 30 washes in accordance withthe WHOPES protocol.

The results show that temperature at heat setting must be at most 20° C.and preferably at most 10° C. below the melting temperature of thepolymer to minimize the loss of deltamethrin from the formed-loop knitof the present invention.

3rd Example Influence of Spin-Finish Wash-Off on Active-IngredientStability During Storage

Example 3 used the same formed-loop knits whose production was describedin Example 1. The samples were investigated, directly after production,with regard to active-ingredient stability following 2 weeks' storage at54° C. These storage conditions were used to simulate a minimumshelf-life of 2 years. Storage took place in a Heraeus ThermoScientifics B620 drying oven. The temperature of 54° C. was constantlymonitored. The net samples were packed for storage in 2 to 4 layers inaluminium foil.

The samples were stored at 54° C. for 2 weeks and then analysed fortheir deltamethrin R-α-isomer content in accordance with the methoddescribed above:

TABLE 3 Fraction of R-α-isomer after storage Temperature at R-α-isomerof deltamethrin heat setting Samples unwashed Samples washed [° C.]prior to heat setting prior to heat setting 110 50.74% 5.07% 120 43.58%5.68% 130 45.74% 4.66% 140 51.11% 5.42%

The results show that washing off the spin finish can be used to reducethe formation of R-α-isomer during storage to below 10%.

4th Example Influence of Atmosphere

Example 4 used the same formed-loop knits whose production was describedin Example 1. The table which follows shows the influence of theatmosphere at heat setting on the loss of deltamethrin during theperformance of washes according to the WHOPES directive. The pieces offormed-loop knit were all heat set at 140° C. for 90 seconds. In theprocess, the atmosphere was varied in the setting oven. Half the piecesof formed-loop knit were heat set in a standard atmosphere withoutaddition of water or steam (dry atmosphere), while the other pieces offormed-loop knit were heat set in the presence of steam.

TABLE 4 Influence of atmosphere at heat setting Number of washes toDeltamethrin Atmosphere WHOPES protocol content [-] [-] [%] Steam 0100%  Dry 0 100%  Steam 5 82% Dry 5 90% Steam 10 84% Dry 10 86% Steam 1579% Dry 15 81% Steam 30 63% Dry 30 69%

The results show that when a dry atmosphere is used during heat settingthe loss of deltamethrin during the washes to WHOPES directive is less.

5th Example Influence of Polypropylene Type on Biological Activity

In this example, the fibres were produced using Metocen® HM 562Spolypropylene and Yuplen® H 893S polypropylene, i.e. during spinning themasterbatch was in each case diluted with one of these polymers.Subsequently, the threads were used to produce a formed-loop knit, inaccordance with the operation described above.

The pieces of formed-loop knit were heat set in a dry atmosphere for 90seconds at different temperatures. Prior to heat setting, the pieces offormed-loop knit were washed in accordance with the procedure describedabove in order to remove the spin finish present on the fibres.

After heat setting, the samples of formed-loop knit were subjected to 20washes in accordance with the WHOPES directive and tested in respect oftheir biological activity as described above.

TABLE 5 Influence of polypropylene type on biological activity after 20washes Temperature of Knock-down Knock-down Mortality Mortality heatsetting Yuplen ® H Metocen ® Yuplen ® H Metocen ® [° C.] 893S HM562S893S HM562S 70 90% 98% 74%  98% 90 64% 98% 66% 100% 110 85% 98% 90% 100%120 86% 95% 74%  93% 130 100%  100%  100%  100% 140 100%  100%  100% 100%

The results show that a higher biological activity is achieved when apolypropylene produced using a metallocene catalyst is used than when apolypropylene produced using a Ziegler-Natta catalyst is used.

6th Example Influence of Different UV Stabilizers on Isomerization ofDeltamethrin

The polymeric materials of the present invention were produced using acorotating close-meshing twin-screw extruder having a screw diameter of34 mm and a housing length of 1200 mm. Extruder temperature housing was200° C. in all steps and extruder speed was 160 rpm. The feed zone ofthe extruder was cooled with water. Total throughput was 20 kg/h.

In a first step, polymer pellets having a concentration of 2% by weightof deltamethrin were produced. To this end, 2% by weight of technicalgrade deltamethrin (BSC AG, Monheim Del.) and 98% by weight ofpolypropylene (Metocen® HMS62S, LyondellBasell, Rotterdam, Netherlands)were mixed in the extruder. All the materials were supplied in solidform to the feed zone of the extruder. The mixture emerged, from theextruder in the form of strands and the strands were cooled in a waterbath. Subsequently, the strands were comminuted by pelletization.

In the second step, polymer pellets containing 1% or 5% by weight of UVstabilizer were produced. To this end, 1% by weight or 5% by weight ofthe UV stabilizer and 99% or 95% by weight, respectively, ofpolypropylene (Metocen® HM562S, LyondellBasell, Rotterdam, Netherlands)were mixed in the extruder. All the materials were supplied in solidform to the feed zone of the extruder. The mixture emerged from theextruder in the form of strands and the strands were cooled in a waterbath. Subsequently, the strands were comminuted by pelletization.

In the third step, the two previously produced pellet productscomprising deltamethrin or UV stabilizer were mixed with polypropylenein the extruder such that a nominal concentration of 1% by weight ofdeltamethrin and a 0.2% by weight concentration of UV stabilizer wereobtained (TK1). To this end, 50% of the pellet product comprisingdeltamethrin, 20% or 4% of the pellet product comprising UV stabilizerand, respectively, 30% or 46% polypropylene were mixed in a tumble mixerand this mixture was extruded using a corotating close-meshingtwin-screw extruder under the abovementioned conditions. The pelletmixture was supplied in solid form to the feed zone of the extruder. Themixture emerged from the extruder in the form of strands and the strandswere cooled in a water bath. Subsequently, the strands were comminutedby pelletization. The pellets contained about 0.9% by weight ofdeltamethrin.

The insecticide-containing polymeric material was used, to produce filmshaving a thickness of about 50 μm. To this end, the polymeric materialwas initially dried at 30° C. for 4 to 17 h. Subsequently, it was meltedin a single-screw extruder and extruded through a film slot die. Thetemperature of the single-screw extruder was varied between 220 and 250°C. The extruded films were withdrawn using a polishing stack. Thetemperature of the first roll of the polishing stack was about 85° C.and the temperature of the second roll of the polishing stack was about60° C.

The following UV stabilizers were used in the tests:

TABLE 6 UV stabilizers Trade name Manufacturing company Chemical classChimasorb ® 2020 BASF (Ciba), Ludwigshafen, Germany 1,6-Hexanediamine,N,N′- bis(2,2,6,6-tetramethyl-4- piperidinyl) polymer with 2,4,6-trichloro-1,3,5-triazine, reaction products with N-butyl-1- butanamineand N-butyl-2,2,6,6- tetramethyl-4-(CAS 192268-64- 7)piperidinamineTinuvin ® 326 BASF (Ciba), Ludwigshafen, Germany Bumetrizole,2-(5-chloro-2H- benzotriazol-2-yl)-6-(1,1- dimethylethyl)-4-methylphenol(CAS 3896-11-5) Tinuvin ® 571 FF BASF (Ciba), Ludwigshafen, GermanyTriazine compound, phenol, 2- (2H-benzotriazol-2-yl)-6-dodecyl-4-methyl-, branched and linear (CAS 125304-04-3) Tinuvin ® 783FDL BASF (Ciba), Ludwigshafen, Germany Poly[[6-[(1,1,3,3-tetramethyl-butyl)amino]-1,3,5-triazin-2,4- diyl][(2,2,6,6-tetramethyl-4-piperidinyl)imino]-1,6-he- xanediyl[(2,2,6,6-tetramethyl-4-piperidinyl)inimo]]), (CAS 71878-19-8), butanedioic acid, dimethylester, polymer with 4- . hydroxy-2,2,6,6-tetramethyl-1- piperidineethanol (CAS 65447- 77-0)

The films were subsequently analysed for their deltamethrin contentusing the abovementioned analytical methods:

TABLE 7 R-α-isomer content Deltamethrin Extrusion (DLT) R-α-isomertemperature content content UV stabilizer [° C.] [% by weight] [% ofDLT] Chimasorb ® 2020 220 0.859 9.989 Chimasorb ® 2020 240 0.883 12.503Chimasorb ® 2020 250 0.888 14.496 Tinuvin ® 326 220 0.986 0.785Tinuvin ® 326 240 0.979 0.000 Tinuvin ® 326 250 0.931 0.868 Tinuvin ®NOR 371 FF 220 0.879 2.471 Tinuvin ® NOR 371 FF 240 0.906 3.713Tinuvin ® NOR 371 FF 250 0.944 4.677 Tinuvin ® 783 FDL 220 0.871 8.999Tinuvin ® 783 FDL 240 0.861 10.858 Tinuvin ® 783 FDL 250 0.882 12.154

The results show that no sterically hindered amines may be used for UVstabilization in order that an isomerization of more than 10% of thedeltamethrin may be prevented in the course of the further processing ofthe polymeric materials of the present invention.

7th Example Prior Art: Coated PET Nets

The insecticide-laden Permanet net from Vestergaard Fraudsen S.A.,Switzerland was evaluated with respect to biological activity anddeltamethrin content. This was followed by repeated performance of thewashing procedure according to the WHOPES protocol and furtherevaluations of biological activity and deltamethrin loss.

The deltamethrin content of the net was determined in the same way asdescribed for the polypropylene net.

TABLE 8 Deltamethrin content and retention index Number of washes toWHOPES Mortality Deltamethrin Retention protocol Knock-down after (DLT)content index [-] after 60 min 24 h [% by weight] [-] 0 100 100 0.208 05 100 100 0.086 84% 10 98 100 0.066 89% 15 97 84 0.059 92% 20 84 720.050 93% 25 69 64 0.040 94% 30 70 61 0.042 95%

The insecticide-laden Permanet net from Vestergaard Frandsen S.A.,Switzerland was tested for active-ingredient stability after 2 weeks'storage at 54° C. These storage conditions are used to simulate aminimum shelf life of 2 years. The samples were stored at 54° C. for 2weeks and subsequently analysed for their deltamethrin R-α-isomercontent in accordance with the method described above. A doubledetermination was carried out.

TABLE 9 R-α-isomer content R-α-isomer of DLT Before 2 weeks' storage at54° C. After 2 weeks' storage at 54° C. 3.35% 47.44% 3.51% 35.35%

The results show that this commercially available net meets the WHOrequirements in respect of knock-down and mortality for 15 washes onlyand has a retention index of less than 95% after 5 washes. Furthermore,the R-α-isomer content after 2 weeks' storage at 54° C. is distinctlymore than 30%.

8th Example Prior Art: PE Nets

The insecticide-laden nets Netprotect® (BESTNET EUROPE LTD., Britain andDuranet® (Clarke Products, USA) were evaluated with respect tobiological activity. This was followed by repeated performance of thewashing procedure to the WHOPES protocol and further evaluations ofbiological activity.

TABLE 10 Biological activity Number of Netprotect ® Duranet ® washesMortality Mortality to WHOPES Knock-down after Knock-down after protocolafter 60 min 24 h after 60 min 24 h [-] [%] [%] [%] [%] 0 100 100 100100 5 93 3 100 98 10 66 44 100 98 15 19 57 95 95 20 7 14 64 70 25 n.d.n.d. 64 70 30 n.d. n.d. 51 51 35 n.d. n.d. 41 41 n.d. = not determined.

The results clearly show that the commercially available nets tested,which are based on polyethylene as fibre material, no longer meet theWHOPES directive in respect of biological activity after distinctlyfewer than 35 washes.

The invention claimed is:
 1. A netlike fabric comprising transfluthrinembedded in at least one polymeric matrix material by mixingtransfluthrin with the polymeric matrix material that is melted to forma mixture, wherein the at least one polymeric matrix material ispolypropylene, wherein the netlike fabric contains from 0.4% to 8% byweight of transfluthrin, and wherein said netlike fabric has abiological activity in accordance with WHOPES guidelines of a knockdownafter 60 minutes of between 95% and 100% after at least 25 washes and amortality after 24 hours of between 80% and 100% after at least 25washes.
 2. The netlike fabric according to claim 1 wherein in accordancewith the WHOPES guidelines the netlike fabric has a retention index r ofthe formula (I) $\begin{matrix}{r = {n\sqrt{\left( {t_{n}/t_{0}} \right)}}} & (I)\end{matrix}$ after at least 5 washes, where t_(n)=total insecticidallyactive ingredient content after n washes (g/kg), t₀=total insecticidallyactive ingredient content after 0 washes (g/kg), and n=number of washes,of at least 95%.
 3. The netlike fabric according to claim 1, wherein thenetlike fabric has a regeneration time of less than 24 hours.
 4. Aprocess for producing the netlike fabric according to claim 1 comprisingmelting the polymeric matrix material and transfluthrin together orseparately at a temperature of between 120 and 250° C., forming themelted mixture into spun threads and cooling, leading the spun threadsthrough a drawing system and drawing, winding the drawn threads in equallength in a parallel arrangement on a bobbin, knitting the wound threadsto form a preliminary netlike fabric, and subjecting the preliminarynetlike fabric to a heat-setting operation.
 5. The process according toclaim 4, wherein a spin finish is used in forming the spun threads. 6.The process according to claim 4, wherein the temperature for theheat-setting operation is 20° C. below the melting temperature of thepolymeric material.
 7. The process according to claim 4, wherein thepreliminary netlike fabric is washed with water and a detergent prior tothe heat-setting operation.
 8. A method for manufacturing a productselected from the group consisting of a woven, braid, knit, felt, andnonwoven, comprising further processing the netlike fabric according toclaim 1 into said product.
 9. A method for manufacturing a sleeping net,comprising further processing the netlike fabric according to claim 1into said sleeping net.
 10. A sleeping net, mosquito net, woven, braid,knit, felt, and nonwoven comprising the netlike fabric according toclaim
 1. 11. A method for producing spun threads comprisingtransfluthrin embedded in a polymeric matrix material that ispolypropylene, the method comprising: a) melting the polymeric materialand transfluthrin together or separately at a temperature of between 120and 250° C., b) forming the melted mixture of step a) into spun threadsand cooling, c) optionally leading the spun threads formed in step b)through a drawing system and drawing, d) subjecting the spun threads toa heat-setting operation wherein the temperature for the heat-settingoperation is 20° C. below the melting temperature of the polymericmaterial wherein the heat-setting operation in step d is preceded by awashing step.
 12. A spun thread produced by the method according toclaim
 11. 13. A method for manufacturing a product selected from thegroup consisting of a sleeping net, mosquito net, woven, braid, knit,felt, and nonwoven, comprising further processing the spun threadaccording to claim 12 into said product.
 14. A netlike fabric comprisingtransfluthrin embedded in a polymeric matrix material that ispolypropylene, the netlike fabric is prepared by a method comprising: a)melting the polymeric material and transfluthrin together or separatelyat a temperature of between 120 and 250° C., b) forming the meltedmixture of step a) into spun threads and cooling, c) optionally leadingthe spun threads formed in step b) through a drawing system and drawing,d) knitting the spun threads to form a preliminary netlike fabric, ande) subjecting the preliminary netlike fabric to a heat-setting operationwherein the temperature for the heat-setting operation is 20° C. belowthe melting temperature of the polymeric material, wherein the netlikefabric contains from 0.4% to 8% by weight of transfluthrin and whereinsaid netlike fabric has a biological activity in accordance with WHOPESguidelines of a knockdown after 60 minutes of between 95% and 100% afterat least 25 washes and a mortality after 24 hours of between 80% and100% after at least 25 washes.
 15. A method for manufacturing a productselected from the group consisting of a sleeping net, mosquito net,woven, braid, knit, felt, and nonwoven, comprising further processingthe netlike fabric according to claim 14 into said product.